反应详情

ca) 50 ml of 33 percent hydrobromic acid in acetic acid are added dropwise within 15 minutes at 10° to 20 g of 4-(benzyloxy)-3-methoxyphenyl 3-pyridyl ketone dissolved in 200 ml of methylene chloride. After stirring at 20° for 3 hours, the reaction mixture is poured into a mixture of 100 ml of conc. aqueous ammonia and ice. The pH is adjusted to 6 by adding acetic acid. The methylene chloride phase is separated; the aqueous phase is extracted twice more with 100 ml of methylene chloride each time. The combined methylene chloride phases are dried over sodium sulfate and evaporated. The residue is recrystallized from methylene chloride/hexane. There is obtained 4-hydroxy-3-methoxyphenyl 3-pyridyl ketone of m.p. 150°-151°.

1. customThe methylene chloride phase is separated
2. extractionthe aqueous phase is extracted twice more with 100 ml of methylene chloride each time
3. dry with materialThe combined methylene chloride phases are dried over sodium sulfate
4. customevaporated
5. customThe residue is recrystallized from methylene chloride/hexane